I recently put a K and N air filter in my 2004 Volusia 800...the problem is when I open the throttle, that the bike bogs and pings until I back off a bit and away it will go and run perfect...I thought maybe it was something to do with the valve setting...I just had the valves checked and set. I put the original factory air filter back in and the bike runs perfect in all ways, even at full throttle. So needless to say the K and N is on the shelf and I ordered a new original factory filter instead of rejetting. I was told that I didnĀ“t need to rejet with the K and N, but apparently I do. Guess the problem was that the bike was running too lean. All is fine now. Was wondering if anyone else had the same experience.